The mother of Democratic congressional candidate Randy Bryce said she was deeply hurt to see a Republican group launching an attack ad featuring Bryce's brother.

Nancy Bryce called for that ad, which is part of a massive $1.5 million media blitz by the Congressional Leadership Fund, to be taken off the air.

"I’m used to my sons getting into disagreements with each other — every mom is. And I understand that my boys see the world differently when it comes to politics," Nancy Bryce wrote in a letter provided to the Journal Sentinel by the Bryce campaign.

"There is now a group of people from Washington who consider it a good idea to pit my boys against each other for their own political gain. But they didn’t consider a mother’s pain at seeing her children used as tools in a political fight, splashed with millions of dollars of ads across the airwaves."

Bryce is running against Republican Bryan Steil to replace House Speaker Paul Ryan, who announced earlier this year he would not seek re-election to the seat for the southeast Wisconsin district.

The ad in question features Milwaukee Police Officer James Bryce discussing why he will be voting for Steil. In it, James Bryce says people don't want to be represented "by someone who’s shown contempt for those in law enforcement."

James Bryce previously contributed money to both Ryan and Steil and even considered running against his brother for the seat.

Nancy Bryce was featured prominently in Randy Bryce's June 2017 campaign launch video, which quickly went viral and helped the union ironworker get national attention, major endorsements and a flood of campaign contributions.

In her letter, Nancy Bryce says she's proud of her children and proud to be the wife of a police officer.

"I was proud of my son Randy when he enlisted in the Army, I supported him through his battle with cancer, and I supported him when he became an ironworker and started fighting on behalf of working families," she wrote. "I am also proud to be the wife of a law enforcement officer, and I am proud of the way we raised all our children. And when Randy told me he was running for Congress, I was so proud and eager to support him."

She added that she's also proud of how her children formed "independent, albeit different, world views."

"Unfortunately, some political operatives see it as a chance to exploit those differences for their own benefit," she wrote.

The James Bryce ad is the second attack ad in as many days released by the super PAC, which is endorsed by Ryan and top House Republicans.

"I might be getting up in years, but I still have some fight in me, and I’m not going to let these people take cheap shots at my boys. I think it might help for people to know the truth," she wrote. "Randy and James’ father was a police officer, and Randy is proud to come from a family of law enforcement officials. He also stands for justice and fairness, and speaks up when he sees a wrong being committed."

Nancy Bryce specifically criticized the Republican Party, as well as Ryan and Steil.

"I am disappointed and, frankly, disgusted that we are at a point where the Republican Party is so focused on sowing division in our families and communities, with such little regard for the truth," she wrote. "Shame on this 'super PAC' for running these ads, shame on its leader Paul Ryan for funding them, and shame on people of good conscience who choose to sit idly by and watch this pain inflicted upon a family in the name of partisan politics."

She called on Steil to disavow the ad and demand it be taken off the air.

Her letter ends with a direct message for Steil.

"Bryan Steil, demand this ad be taken off the air. This goes too far," she wrote. "However the election turns out, politics should not be handled like this."

On Thursday, James Bryce raised questions about the letter — and who wrote it — during an interview with conservative radio host Jay Weber.

"As soon as I read the reply, my immediate response was that's not her. That's not her writing. That's not how she talks," he said. "After talking to her, I feel confident in saying that I think it's unconscionable that a campaign would take advantage of a vulnerable and elderly mother."

James Bryce insisted that his mother "definitely had some help" writing the letter.

But in an interview Thursday morning, Nancy Bryce told the Journal Sentinel, "I did write the letter, and those are my words."